new assignment controller
finish assignment controller and view
finish handling questionnaire and due_date
ready to merge
merged new assignment controller
remove dead code in assignment.rb
remove assignments_helper.rb (duplicated, deprecated, dead code)
Fixes a bug that caused a Rails error when an instructor tried to copy
an assignment team to a course, but the assignment was not associated
with the course.  Now, the instructor is warned, and given a link to
"Fix this."

Also renames some files and methods to be more suggestive of their
functionality.

And fixes the first line of assignment_controller.rb>>update (though
this might have already been fixed in another branch.
refactored assignment model move function to assignment helper
rename views/assignment/_content.html.erb to _general.html.erb
move assignment/edit related stubs to views/assignment/edit folder.
delete _availability_flag
Merge remote-tracking branch 'origin/master'

Conflicts:
	app/controllers/assignment_controller.rb